Background and Objectives Pilomatricoma is a frequently diagnosed skin lesion of the head and neck that may often be misdiagnosed as other skin lesions. This study evaluated whether ultrasonography (USG) or computed tomography (CT) is the most helpful imaging modality for the accurate preoperative diagnosis of pilomatricoma in head and neck regions of children and adolescents.Subjects and Method A retrospective review was conducted for 59 patients with pilomatricoma under the age of 19 years. All cases were pathologically confirmed with pilomatricoma in the head or neck.Results Preoperative imaging examinations were performed with USG in six cases and with CT in nine cases. The accuracy of preoperative diagnosis was compared between three groups: 1) with clinical findings only, 2) with USG, and 3) with CT. The correct preoperative diagnosis was made in 18 (30.5%) of the total of 59 cases. Using only clinical findings, 10 (22.7%) out of 44 patients were diagnosed as pilomatricoma. With the addition of USG, pilomatricoma was diagnosed in 1 (16.7%) out of six cases, whereas with the addition of CT, 7 (77.8%) out of 9 cases (77.8%) were diagnosed correctly. Preoperative diagnosis of pilomatricoma with CT imaging was more accurate than clinical findings only (vs. CT; odds ratio [OR]=11.900, 95% confidence interval [CI] 2.126-66.615; p=0.001) or USG (vs. CT; OR=17.500, 95% CI 1.223-250.357; p=0.020).Conclusion In the preoperative diagnosis of pilomatricoma, imaging modalities such as CT and USG are helpful, with CT offering higher diagnostic accuracy and USG procedural benefits in younger children.

Background and Objectives This study examined the expressions of p16 and the programmed cell death 1 ligand (PD-L1) in patients with oropharyngeal cancer (OPC) treated with radiotherapy (RT) to identify the correlation between p16 and PD-L1 expression, and to examine the prognostic significance of these markers for OPC patients receiving RT. Subjects and Method Forty-eight OPC patients diagnosed and treated at a tertiary referral hospital were enrolled in this retrospective analysis. Patients were initially treated with RT or chemoradiotherapy (CRT) with curative intent and completed the planned schedule. Expression of p16 and PD-L1 by primary tumors was evaluated by immunohistochemistry, and results were interpreted separately and dichotomized according to outcome analyses. Results Of the 48 patients, 25 (52.1%) expressed p16 and 15 (31.3%) expressed PD-L1. Expression of these markers showed a mutual positive correlation (p=0.046). Positive PD-L1 expression was associated with poor complete remission (CR) rates after RT (p=0.040). Positive p16 expression was associated with better recurrence-free survival (RFS) (p=0.004) but not overall survival (OS) (p=0.192). PD-L1 expression showed no independent association with survival (p>0.05); however, PD-L1 expression tended toward poorer RFS, even in p16-positive individuals. Conclusion There was a positive correlation between the expression of p16 and PD-L1 in OPCs. PD-L1 expression was associated with poorer CR rates after RT or CRT. PD-L1 alone did not show an association with RFS or OS, but when combined with p16, it tended toward poorer RFS, even in p16-positive cases.